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300-420 · Question #251
300-420 Question #251: Real Exam Question with Answer & Explanation
The correct answer is B: 6to4. 6to4 is an automatic IPv6-over-IPv4 tunneling mechanism that embeds an IPv4 address in the IPv6 address (2002::/16 prefix) to allow IPv6 islands to communicate across an IPv4 backbone.
Advanced Addressing and Routing Solutions
Question
Refer to the exhibit. Which method must an architect use to provide connectivity between the mail servers?
Options
- AISATAP
- B6to4
- C6rd
- DIPv4 compatible
Explanation
6to4 is an automatic IPv6-over-IPv4 tunneling mechanism that embeds an IPv4 address in the IPv6 address (2002::/16 prefix) to allow IPv6 islands to communicate across an IPv4 backbone.
Common mistakes.
- A. ISATAP (Intra-Site Automatic Tunnel Addressing Protocol) is designed to connect individual IPv6 hosts within a single site over an IPv4 intranet, not to interconnect separate IPv6 networks.
- C. 6rd (IPv6 Rapid Deployment) is a service-provider mechanism that uses ISP-assigned prefixes to deploy IPv6 over an ISP's IPv4 infrastructure, not a general-purpose site-to-site tunneling solution.
- D. IPv4-compatible IPv6 addresses (::x.x.x.x) are deprecated per RFC 4291 and are not a supported or viable tunneling mechanism in modern networks.
Concept tested. 6to4 automatic tunneling for IPv6 over IPv4
Topics
#IPv6 Transition Mechanisms#6to4 Tunneling#IPv6 Connectivity#Network Architecture
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